1. Field of the Invention
The present invention relates to an ultrasonic cancer treatment enhancer for enhancing ultrasonic cancer treatment by exposing an affected part to ultrasonic waves, and a cell killer which, upon exposure to ultrasonic waves, can be rendered cytotoxic and can kill target cells to be killed, such as cancer cells.
2. Background Art
In recent years, in cancer treatment, sonodynamic therapy, which is noninvasive and can efficiently treat an affected part, has been proposed from the viewpoint of simultaneously improving both therapeutic effect and QOL (quality of life) of patients. According to the sonodynamic therapy, an administered medicament, which is used in combination with ultrasonic waves, is rendered antitumor-active by ultrasonic irradiation to treat the tumor. A method using fullerene as an agent to be used in combination with ultrasonic therapy is known (see, for example, Japanese Patent Laid-Open No. 241307/2002 and WO 2002/66061). A method using pigment as an agent to be used in combination with ultrasonic therapy is also known (see, Japanese Patent Laid-Open No. 253836/2001, WO98/1131, and Japanese Patent Laid-Open No. 226654/2003). According to the above methods, treatment is carried out by exciting organic matter or fullerene, which produces radical species upon exposure to light, by ultrasonic effect.
On the other hand, a proposal has been made in which the photocatalytic activity of titanium oxide is utilized for cancer treatment. For example, the utilization of titanium oxide as a medical device (see Japanese Patent Laid-Open No. 357941/1992) and as a carrier for a drug delivery system (DDS) (see Japanese Patent Laid-Open No. 200050/2001 and U.S. Pat. No. 6,677,606) has been proposed.
Further, a technique has also been proposed in which titanium oxide having a particle size of 2 to 3 mm is exposed to ultrasonic waves of 35 to 42 kHz to generate hydroxy radicals which decompose organic matter (see, for example, Japanese Patent Laid-Open No. 26406/2003).